The method is thoroughly operator-algebraic and in the most abstract setting of
Section  no field picture (wedge-local or not) is required. On the other
hand, the interaction is fairly weak. When the field description is available, a pair
of particles of different species obtains a phase during the interaction
and no momentum transfer occurs.
A connection with wedge-local field approach and our previously constructed Borchers triples
has been found in [1]}.
It is worth investigating how to obtain more general
integrable models (e.g. [2]}, [3]}) purely operator-algebraically, where
a “self-interaction” occurs.
